CVE-2026-23999 Fleet: Device lock PIN can be predicted if lock time is known
Attackers with physical access and timing knowledge can predict device lock PINs due to weak entropy, bypassing lock controls.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23999?
CVE-2026-23999 is a low-severity vulnerability in fleetdm fleet, published on 26 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Fleet is open source device management software. In versions prior to 4.80.1, Fleet generated device lock and wipe PINs using a predictable algorithm based solely on the current Unix timestamp. Because no secret key or additional entropy was used, the resulting PIN could potentially be derived if the approximate time the device was locked is known. Fleet’s device lock and wipe commands generate a 6-digit PIN that is displayed to administrators for unlocking a device. In affected versions, this PIN was deterministically derived from the current timestamp. An attacker with physical possession of a locked device and knowledge of the approximate time the lock command was issued could theoretically predict the correct PIN within a limited search window. However, successful exploitation is constrained by multiple factors: Physical access to the device is required, the approximate lock time must be known, the operating system enforces rate limiting on PIN entry attempts, attempts would need to be spread over, and device wipe operations would typically complete before sufficient attempts could be made. As a result, this issue does not allow remote exploitation, fleet-wide compromise, or bypass of Fleet authentication controls. Version 4.80.1 contains a patch. No known workarounds are available.
Weakness: CWE-330
Which versions are affected by CVE-2026-23999?
3 open source packages ship an affected version, including github.com/fleetdm/fleet/v4. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
Products include Fleetdm Fleet.
How do I fix CVE-2026-23999?
Upgrade github.com/fleetdm/fleet/v4 to 4.80.1 or later.
Is CVE-2026-23999 being exploited?
There is no known exploitation of CVE-2026-23999 in the wild and no public exploit code.
Other vulnerabilities in fleetdm fleet
- CVE-2020-26276 SAML authentication vulnerability in Fleet
- CVE-2026-103264 Fleet before 4.87.0 Authentication Bypass via Device Identifiers
- CVE-2026-23518 Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
- CVE-2026-26062 Fleet server may terminate unexpectedly when handling certain gRPC requests
- CVE-2026-26061 Fleet's unbounded request body read allows remote Denial of Service
Sources
Also known as GHSA-ppwx-5jq7-px2w, GO-2026-4564.